In a two family unit, the owner is changing all of the gas appliances to electric , so we are upgrading the services to handle the demand(each unit has its own service).The house has one water service from the street,once it comes through the basement wall it's T'd off and goes to two seperate water meters.My questions are, do I bond both services to this one underground water pipe? And do I jumper around both water meters to bond each units metal water piping systems to this same underground water pipe?Thanks in advance for any help.
bonding water pipe in duplex
- Thread starter dave683
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jtester
Senior Member
- Location
- Las Cruces N.M.
Re: bonding water pipe in duplex
dave683
I believe that you are going to want to both ground and bond the water system.
First if you can get to within 5' of where the metal water pipe enters the building, you will use it as one of the grounding electrodes, see 250.53(D).
Secondly you will need to bond the water piping systems, see 250.104 in particular 250.104(2)
Our inspectors require that the hot and cold pipes entering and leaving a water heater be bonded together since the hot water pipe is not continuous to the cold water connections.
Jim T
dave683
I believe that you are going to want to both ground and bond the water system.
First if you can get to within 5' of where the metal water pipe enters the building, you will use it as one of the grounding electrodes, see 250.53(D).
Secondly you will need to bond the water piping systems, see 250.104 in particular 250.104(2)
Our inspectors require that the hot and cold pipes entering and leaving a water heater be bonded together since the hot water pipe is not continuous to the cold water connections.
Jim T
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Re: bonding water pipe in duplex
I did an installation like this over the summer. It was a duplex with a double meter pan offset nippled to two 100A service diconnects. What made it interesting was my utility requires the grounding electrode conductor to loop thru the ground rod(s), back to the main and redundantly terminate. So I came out of one disconnect, hit the ground rod and went into the other disconnect, then ran a jumper between the two discons to satisfy the loopback. Then the water bond went to one of the disconnects. I am curious why bonding the hot and cold of a water heater would be necessary, if each terminus consists of a threaded nipple threaded into the tank?
I did an installation like this over the summer. It was a duplex with a double meter pan offset nippled to two 100A service diconnects. What made it interesting was my utility requires the grounding electrode conductor to loop thru the ground rod(s), back to the main and redundantly terminate. So I came out of one disconnect, hit the ground rod and went into the other disconnect, then ran a jumper between the two discons to satisfy the loopback. Then the water bond went to one of the disconnects. I am curious why bonding the hot and cold of a water heater would be necessary, if each terminus consists of a threaded nipple threaded into the tank?
jtester
Senior Member
- Location
- Las Cruces N.M.
Re: bonding water pipe in duplex
electrofelon
Some of our inspectors believe that there is not a continuous electrical path from cold thru the tank to hot.
Jim T
electrofelon
Some of our inspectors believe that there is not a continuous electrical path from cold thru the tank to hot.
Jim T
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Re: bonding water pipe in duplex
yeah i guess there could be corrosion or pipe dope on the threads resulting in a less than perfect connection...
yeah i guess there could be corrosion or pipe dope on the threads resulting in a less than perfect connection...
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: bonding water pipe in duplex
Ironically, some AHJ's around here (namely Cheyenne) require the hot-cold bond even when the house is run entirely in plastic plumbing. Go figure.
No sense, no headaches I guess...
Ironically, some AHJ's around here (namely Cheyenne) require the hot-cold bond even when the house is run entirely in plastic plumbing. Go figure.
No sense, no headaches I guess...
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: bonding water pipe in duplex
I wonder why metallic water pipes must always be bonded, yet other metal piping systems need only be bonded if they are "likely to become energized"?
I wonder why metallic water pipes must always be bonded, yet other metal piping systems need only be bonded if they are "likely to become energized"?
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